1. Technical Field of the Invention
The present invention relates generally to memory and more particularly methods for accessing memory systems.
2. Background Information
Many types of devices require memory for the operation of the device. Such devices may include cellular phones and personal organizers. The total memory available to the device may include “virtual” and “physical” memory. Physical memory may be accessed via physical memory addresses and may take the form of random access memory (RAM) circuits that physically exist in the device. In contrast to physical memory, virtual memory may be accessed via virtual memory addresses and may take the form of a slower access magnetic storage medium (e.g., a disk drive) that performs functions similar to physical memory. For example, a hard drive may store and retrieve data similar to a RAM circuit. Virtual memory typically is used when a device does not have enough physical memory to store all applications that the user desires to run concurrently.
Some devices with virtual and physical memory may execute sensitive applications, such as user authentication and encryption, in a “secure” operating mode. The secure operating mode may provide a secure environment in which the sensitive applications may not have access to virtual memory. Thus, the sensitive applications may retrieve input and store output from only physical memory. However, the input and output to the sensitive applications desirably may reside in virtual memory. Efficient techniques that convert virtual memory addresses to physical memory addresses, thereby enabling the execution of the sensitive applications, are desirable.